app.py

import cv2
import numpy as np
import gradio as gr
from skimage.metrics import structural_similarity as compare_ssim


def ascii_art_generator(input_image, contrast, threshold1, threshold2, ascii_chars):
    # Resize the image
    new_width = 100
    height, width = input_image.shape[:2]
    aspect_ratio = height / width
    new_height = int(aspect_ratio * new_width * 0.55)
    resized_image = cv2.resize(input_image, (new_width, int(new_height)))

    # Convert to grayscale
    gray_image = cv2.cvtColor(resized_image, cv2.COLOR_BGR2GRAY)

    # Apply transformation algorithm with user parameters
    adjusted_image = cv2.convertScaleAbs(gray_image, alpha=contrast, beta=0)
    edges = cv2.Canny(
        adjusted_image, threshold1=int(threshold1), threshold2=int(threshold2)
    )
    processed_image = cv2.bitwise_not(edges)

    # Map intensities to ASCII characters
    def pixel_to_ascii(pixel_value):
        num_chars = len(ascii_chars)
        index = int(pixel_value / 255 * (num_chars - 1))
        return ascii_chars[index]

    # Generate the ASCII art string
    ascii_art_lines = []
    for row in processed_image:
        line = "".join([pixel_to_ascii(pixel) for pixel in row])
        ascii_art_lines.append(line)
    ascii_art = "\n".join(ascii_art_lines)

    # Save the ASCII art to a text file
    with open("ascii_art.txt", "w") as f:
        f.write(ascii_art)

    # Convert processed_image to RGB format for display
    processed_image_rgb = cv2.cvtColor(processed_image, cv2.COLOR_GRAY2RGB)

    # Convert ASCII art back to image
    def ascii_to_image(ascii_art, ascii_chars):
        # Create a mapping from characters to grayscale values
        char_to_intensity = {
            char: int(i / (len(ascii_chars) - 1) * 255)
            for i, char in enumerate(ascii_chars)
        }
        ascii_lines = ascii_art.split("\n")
        height = len(ascii_lines)
        width = len(ascii_lines[0]) if height > 0 else 0
        ascii_image = np.zeros((height, width), dtype=np.uint8)
        for y, line in enumerate(ascii_lines):
            for x, char in enumerate(line):
                ascii_image[y, x] = char_to_intensity.get(char, 0)
        return ascii_image

    ascii_image = ascii_to_image(ascii_art, ascii_chars)

    # Normalize the original image
    def normalize_images(original_image, ascii_image_shape):
        resized_original = cv2.resize(
            original_image, (ascii_image_shape[1], ascii_image_shape[0])
        )
        if len(resized_original.shape) == 3:
            resized_original = cv2.cvtColor(resized_original, cv2.COLOR_BGR2GRAY)
        return resized_original

    normalized_original = normalize_images(gray_image, ascii_image.shape)

    # Calculate similarity metrics
    def calculate_mse(image1, image2):
        mse = np.mean((image1.astype("float") - image2.astype("float")) ** 2)
        return mse

    def calculate_ssim(image1, image2):
        ssim, _ = compare_ssim(image1, image2, full=True)
        return ssim

    def calculate_psnr(image1, image2):
        mse = calculate_mse(image1, image2)
        if mse == 0:
            return float("inf")
        PIXEL_MAX = 255.0
        psnr = 20 * np.log10(PIXEL_MAX / np.sqrt(mse))
        return psnr

    mse = calculate_mse(normalized_original, ascii_image)
    ssim = calculate_ssim(normalized_original, ascii_image)
    psnr = calculate_psnr(normalized_original, ascii_image)

    # Prepare metrics output
    metrics_text = f"MSE: {mse:.2f}\nSSIM: {ssim:.4f}\nPSNR: {psnr:.2f} dB"

    return ascii_art, "ascii_art.txt", processed_image_rgb, metrics_text


# Define the Gradio interface using the updated components
iface = gr.Interface(
    fn=ascii_art_generator,
    inputs=[
        gr.Image(type="numpy", label="Upload Image"),
        gr.Slider(0.5, 3.0, step=0.1, value=1.5, label="Contrast"),
        gr.Slider(0, 255, step=1, value=50, label="Edge Detection Threshold1"),
        gr.Slider(0, 255, step=1, value=150, label="Edge Detection Threshold2"),
        gr.Textbox(value="@%#*+=-:. ", label="ASCII Characters (Dark to Light)"),
    ],
    outputs=[
        gr.Textbox(label="ASCII Art"),
        gr.File(label="Download ASCII Art as Text File"),
        gr.Image(type="numpy", label="Processed Image"),
        gr.Textbox(label="Performance Metrics"),
    ],
    title="Interactive ASCII Art Generator with Performance Metric",
    description="Upload an image and adjust parameters to convert it into ASCII art. The performance metric quantifies the similarity between the original image and the ASCII art.",
    allow_flagging="never",
)

iface.launch(debug=True, share=True)